The present invention relates to a process and apparatus for removing nitric oxide constituents from the exhaust gases of nitric-oxide processing installations, in particular nitric acid plants, through catalytic reduction with ammonia or ammonia-containing agents.
The emission of nitric oxides is detrimental to the environment. Accordingly, it is important to maintain within permissible limits the amount of nitric oxides emitted to the atmosphere in a process. Nitric acid plants ordinarily discharge nitric oxides in amounts which are far above normally permissible limits.
German Pat. No. 1,259,298 discloses a process wherein exhaust gas is treated after the primary processing operation, such as the production of nitric acid, and the purified exhaust gas is led directly to the atmosphere through a flue chimney.